Mr Patarkatsishvili backed Georgia's 2003 "Rose Revolution"

The state prosecutor has also frozen a bank account belonging to Mr Patarkatsishvili, who lives abroad.

In November the authorities temporarily shut down Imedi TV, the main outlet for opposition views, which is co-owned by Mr Patarkatsishvili.

Georgian President Mikhail Saakashvili won re-election in a 5 January poll.

Mr Patarkatsishvili, a multi-millionaire who lives in self-imposed exile in Britain and Israel, was a rival candidate.

The state prosecutor charged him on Thursday with "conspiracy to overthrow the Georgian government" and with "plotting an attack on a Georgian politician".

The statement said he must appear at the prosecutor's office.

Political tensions

The authorities say he offered a $100m (�50m) bribe to a senior police official to help him overthrow the government and seize the Georgian interior minister. Mr Patarkatsishvili denies that.

President Saakashvili called the snap election after huge opposition street protests.

He sent in riot police to quell the protests in November. He also imposed a state of emergency - later lifted - and alleged there was a hidden Russian hand in the unrest.

Mr Patarkatsishvili has accused the authorities of targeting his business assets and has spoken of a plot to kill him. He did not return to Georgia for the election, and won only 7% of the vote.

President Saakashvili, a US-educated lawyer, came to power after street protests in 2003, nicknamed the Rose Revolution.

His first term as president saw Georgia strengthen its ties with Nato while relations with Moscow soured.